There are a bumper crop of papers in this edition of the Arabidopsis Research Roundup. First from the University of Manchester is a paper that identifies a protein involved in plant programmed cell death. Secondly are two papers from the University of Bristol that highlight the role of viruses in the reflectivity of plant leaves and an assessment of the growth parameters of Arabidopsis on different soil-types. Thirdly are three papers from University of Edinburgh that either use CRISPR-Cas technology to develop virus-research plants, investigate the relationship between photoperiod and metabolism or present a method for assessment of protein S-nitrosylation. Fourthly is a paper that includes a contribution from the University of Leeds that investigates the evolutionary and functional relationship of the WOX gene family. Finally is a study that highlights the role of the AUGMIN complex during microtubule activity that includes a contribution from the University of Leicester.

In addition, although not involving Arabidopsis, we should mention an exciting study from Gerben van Ooijen (Edinburgh) that has discovered a conserved circadian mechanism based on magnesium rhythms that is linked to energy expenditure.

The corresponding author of this paper is Patrick Gallois from the University of Manchester and includes contributions from Hazel McLellan in Dundee almongside Chinese and Austrian collaborators. This study investigates the role of caspase proteins on control of programmed cell death in plants. This research area has been hindered by the apparent lack of plant caspase orthologues despite pharmacological evidence that proteins with caspase activity are active in plants. The authors use a labeled caspase-3 inhibitor to identify the Arabidopsis Cathepsin B3 (AtCathB3) protein as having caspase activity, which was verified using recombinant proteins during in vitro enzyme assays. AtCathepsinB1,2,3 triple mutant plants demonstrate a reduction in PCD induced by different stresses and explains why caspase inhibitors are effective tools for studying PCD in plants. The core Cathepsin B protein is evolutionarily conserved suggesting that an ancestral pathway exists that controls PCD, the details of which require further study.

Gary Foster’s research group at the University of Bristol collaborate with others at the University of York and in Australia for this study that investigates how plant viruses may modify gene expression to benefit their own transmission. They show that Potato virus Y and Cucumber mosaic virus (CMW), which both are transmitted by aphids, significantly reduce the amount of polarised light that is reflected from abaxial leaf surfaces of tobacco plants particularly when compared to the effects caused by non-insect vectored viruses. However this effect was not shown in Arabidopsis leaves infected by a variety of differently transmitted viruses. Interestingly ECERIFERUM6 (CER6) transcripts accumulate to higher levels following infection with insect vectored viruses and as this gene is involved in cuticle wax synthesis the authors suggest that induced changes in cuticle composition might be key in understanding how viruses encourage predation by their insect vectors. Finally the authors discuss the overall adaptive significance of these results.

GARNet committee member Anthony Dodd, also from the University of Bristol, leads this study into the growth of Arabidopsis on peat-free media, which was motivated by the unsustainable use of peat-based composts. They found that biomass accumulation and seed yield were reduced on peat-free media and that some types of this media was more suspectible to fungal contamination. Overall vegetative phenotypic parameters were similar between plants grown on peat-based or peat-free media, indicating that this type of media will be appropriate for future analysis. However the seed yield was usually reduced, indicating that experiments looking at post-phase change phenotypes might not be as comparable between plants growth on media with different amount of peat.

Attila Molnar (Edinburgh) is the corresponding author on this study that uses the transformative technology CRISPR/Cas9 to engineer Arabidopsis plants that are resistant to potyvirus infection. This is achieved by targeting the genes encoding the translation initiation factor eIF(iso)4E that had been previously identified as being critical for viral establishment. Importantly they subsequently selected transgene-free plants that have no phenotypic changes when compared to wildtype growth under standard conditions. As the potyvirus Turnip Mosaic Virus is an important pathogen for vegetable crops this is potentially an extremely powerful technique for generating virus-resistance food crops.

This German–led study aims to connect the expression of photoperiod-length responsive circadian clock-regulated genes with those involved in metabolic processes such as starch degradation and includes a contribution from Professor Andrew Miller from the Edinburgh SynthSys Centre. The authors assess global gene expression by transcript profiling at photoperiods ranging from 4-18 hours and found that changes in transcript abundance at dawn throughout these photoperiods were as large as changes seen in individual experiments when comparing dawn and dusk. These complex interactions revealed coordinated regulation of key metabolic processes and begins to demonstrate how metabolism is linked to photoperiod.

This paper from the lab of Gary Loake (Edinburgh) describes the methods they use to investigate the role of protein S-nitrosylation in the immune responses of Arabidopsis. These are based on a modification of the biotin-switch technique, which they term sequential cysteine blocking.

This German-led study includes work from the lab of Brendan Davies at the University of Leeds and investigates the role of the WUSCHEL-RELATED HOMEOBOX (WOX) transcription factor gene family during stem cell development and maintenance. Most members of the WUS-clade can largely substitute for WUSCHEL activity in the shoot meristem, which is absolutely dependent on a conserved WUS-box motif that is critical for the interaction with TOPLESS co-repressors. In contrast to the WUS clade, the WOX13 and WOX9 clades cannot substitute for WUS activity. The indicates that WOX control of shoot and floral meristem relies on certain currently not-fully-understood attributes of the WUS-clade of proteins.

David Twell (Leicester) is an author on his Korean-led study that reports on the identification of the new gem3 mutant, which displays defects in gametophytic development. Mutant plants exhibits disrupted cell division during male meiosis, at pollen mitosis I and throughout female gametogenesis. Gem3 is a hypomorphic allele of the AUGMIN subunit 6 gene, which is a component of Augmin complex responsible for microtubule (MT) nucleation in acentrosomal cells. In the gem3 mutant, the authors show that MT arrays are incorrectly distributed, likely causing the gametophyte-specific phenotypes and demonstrating a broad role for the augmin complex during sexual reproduction in flowering plants

This Arabidopsis Research Roundup has five papers that includes two from the John Innes Centre and two from the University of Edinburgh. Firstly Kristen Bomblies’s group at the JIC have investigated the relationship between temperature and meiotic recombination rates. Secondly Veronica Grieneisen and Stan Maree have developed a mathematical model to characterise cell morphologies taken[…]

The first two papers in this weeks Arabidopsis Research Roundup investigate different aspects of the plants response to temperature fluctuations. Firstly Lars Ostergaard (JIC) looks at the influence of temperature in the control of fruit dehiscence whilst Phil Wigge (SLCU) investigates crosstalk between chloroplast and nuclear signaling. The third paper from Ian Henderson (University of[…]

Charles Melnyk discusses a new paper published in PNAS that describes the molecular events that occur during grafting. The paper is entitled ‘Transcriptome dynamics at Arabidopsis graft junctions reveal an intertissue recognition mechanism that activates vascular regeneration‘ http://blog.garnetcommunity.org.uk/wp-content/uploads/2018/03/Melynk_180301.mp3Podcast: Play in new window | DownloadSubscribe: iTunes | Android | RSS

This edition of the Arabidopsis Research roundup beings with a study from SLCU that provides a molecular context to the changes that occur at graft junctions. Second is a study from Edinburgh that reports on the findings of a citizen science plant phenotyping project. Third are two studies from the John Innes Centre that follow-on[…]

This weeks Arabidopsis Research Roundup begins with a study from SLCU that investigates the interaction between nitrate and cytokinin signaling in the shoot meristem. Next is research from Sheffield that studies changes to the macromolecular composition of the photosynthetic apparatus following the transition from dark to light. Third are three papers that include University of[…]

GARNet with support from the Bristol Centre for Agricultural Innovation and New Phytologist are organising a Gene Editing Workshop that will take place at the University of Bristol on March 26th-27th 2018. This workshop is designed to encourage interactions and discussion about the use of CRISPR-Cas9 gene editing in plant systems. We are encouraging ECRs[…]

The cellular mechanics of auxin perception and signaling have been well studied over the past two decades. The pivotal interaction that controls this activity involves the auxin-dependent contact between the TIR1 receptor and a family of transcriptional regulators called AuxIAA proteins. This interaction has been characterised at a structural level with the auxin indole-3-acetic acid[…]

This weeks Arabidopsis Research Roundup begins with two papers from Royal Hollaway University of London that investigate the factors that control leaf development in the dark and the control of PIN1 phosphorylation. Third is a paper from Bristol that demonstrates the translation of research from Arabidopsis into coriander with regard the control of the response[…]

Enrique Lopez-Juez (Royal Holloway University of London) introduces a paper from that attempts to answer a critical question in plant science ‘Why do plants makes leaves in the dark‘? http://www.plantphysiol.org/content/early/2017/12/28/pp.17.01730.long http://blog.garnetcommunity.org.uk/wp-content/uploads/2018/01/Lopez_180116.mp3Podcast: Play in new window | DownloadSubscribe: iTunes | Android | RSS